1. Technical Field
This application concerns a chucking device for a drill tool, such as with one drill tip each at every end of the tool. In this connection, a drill tool means a drill intended to generate a boring with a constant diameter just as well as, for example, a step drill or a countersinking tool.
2. Background Information
Such a chucking device with a cylindrical adapter sleeve is known, for instance, from DE 203 16 350, U1. The adapter sleeve described there also serves to house a drill tool having a constant drill or external diameter over its entire drill length, such drill tool featuring one drill tip at each end. However, said chucking device cannot be used for a drill tool, whose external diameter increases towards its drill ends or its drill tips.
For a drill tool of this embodiment a solution is described in accordance with DE 103 37 203, A,, which requires the insertion of a twisted flute on the inside of the chucking device. This drill tool is conducted along said twisted flute when being inserted in the adapter sleeve. The unavoidable manufacturing tolerances and the high production expenditures to insert the twisted flutes into the inner surface of the chucking device represent a disadvantage of the described embodiment. Moreover, the percentage contact area for the drill tool is low, since said drill tool is held inside the adapter sleeve only between the two backs of the drill. Furthermore, inserting the twisted flute in the inner surface weakens the wall or the sleeve of the chucking device, thus either negatively influencing the stability, or requiring increased material and thus cost expenditures in thick-walled embodiments as compared to a design with smooth walls on the inside. An additional disadvantage is that only drill tools featuring an ascending slope compatible with the inserted twisted flute can be clamped.